Description of On-Board Diagnostics

A self-diagnosis function is built into the electronic control system. Warning is indicated by the "O/D OFF" indicator light.

- If a malfunction occurs within the speed sensors (No.1 or 2) or solenoids (No.1 or 2), the "O/D OFF" light will blink to warn the driver.

- A malfunction with the lock-up solenoid will set a code but will not cause the indicator to flash.

- The diagnostic code can be read by the number of blinks of the "O/D OFF" indicator light when terminals TE1 and E1 of DLC1 or DLC2 are connected.

- The throttle position sensor or brake signal are not indicated, but inspection can be made by checking the voltage at terminal Tt of DLC2.

- The signals to each gear can be checked by measuring the voltage at terminal Tt of DLC2 while driving.

- The diagnostic trouble code is retained in memory by the ECM and due to back-up voltage, is not canceled out when the engine is turned off. Consequently, after repair, it is necessary to turn the ignition switch OFF and remove the "EFI" fuse (15A) or disconnect the ECM connector (for 10 seconds or more), to cancel out the diagnostic trouble code.


NOTE:
^ Low battery voltage will cause false operation of the diagnosis system.
^ Use a voltmeter and ohmmeter that have an impedance of at least 10 K Ohms.
^ Diagnostic trouble codes can be read only when the overdrive switch is ON (IN). If OFF (OUT), the "O/D OFF" light is lit continuously and will not blink.